ALL THINGS CONSIDERED: When you’ve played Austin Powers, Shrek, The Cat in the Hat and the title dweeb in Wayne’s World, what do you do for an encore? If you’re comedian Mike Myers, the next logical step, evidently, is to direct a documentary about your agent. And damned if it doesn’t turn out to be a decent career move — as smart, and sometimes even as funny, as anything Myers has done recently. Not that Supermensch: The Legend of Shep Gordon is likely to do the kind of business most Myers movies do (might do as well as The Love Guru, I suppose), but it’s competent enough to suggest the filmmaker has more arrows in his quiver than “yeah, baby.” He starts the film with five minutes of celebrity testimonials telling you why you should care about this guy you’ve never heard of — Willie Nelson calling Gordon the “proverbial canary in the marijuana mine,” chef Emeril Lagasse saying Gordon invented the concept of celebrity chef, a parade of film stars testifying to his libido (Michael Douglas remembers a T-shirt emblazoned with “No Head, No Backstage Pass”). And then, an obviously hero-worshipping Mike Myers lets the man himself take over — Gordon recounting how in 1968, he arrived in a Los Angeles motel, fresh out of college, with no money, no job, having just dropped some acid, utterly at peace with the world, and got slugged by a gal who later identified herself as Janis Joplin. She introduced him to Jim Morrison and Jimi Hendrix, who suggested that, since he was Jewish, he should become a manager. “Who should I manage?” wondered Gordon. “Alice Cooper,” came the reply. MORE